Chaves YC, Genaro K, Stern CA, de Oliveira Guaita G, de Souza Crippa JA, da Cunha JM and Zanoveli JM

Neurosci Lett (2020) 729: 135020

Link to abstract

The prevalence rates of depression and anxiety are at least two times higher in diabetic patients, increasing morbidity and mortality. Cannabidiol (CBD) has been identified as a therapeutic agent viable to treat diverse psychiatric disorders. Thus, this study aimed to investigate the effect of CBD treatment (once a day for 14 days starting two weeks after diabetes induction; at doses of 0, 3, 10 or 30 mg/kg, i.p.) on depression- and anxiety-like behaviors associated with experimental diabetes induced by streptozotocin (60 mg/kg; i.p.) in rats. Levels of plasma insulin, blood glucose, and weight gain were evaluated in all experimental groups, including a positive control group treated with imipramine. The rats were tested in the modified forced swimming test (mFST) and elevated plus maze (EPM) test. Besides, the levels of serotonin (5-HT), noradrenaline (NA) and dopamine (DA) in two emotion-related brain regions, the prefrontal cortex (PFC) and hippocampus (HIP) were evaluated using high-pressure liquid chromatography. Our results showed that CBD treatment (only at the higher dose of 30 mg/kg) reduced the exaggerated depressive- and anxiogenic-like behaviors of diabetic (DBT) rats, which may be associated with altered 5-HT, NA and/or DA levels observed in the PFC and HIP. Treatment with CBD (higher dose) also induced a significant increase in weight gain and the insulin levels (and consequently reduced glycemia) in DBT rats. The long-term CBD effects gave rise to novel therapeutic strategies to limit the physiological and neurobehavioral deficits in DBT rats. This approach provided evidence that CBD can be useful for treating psychiatry comorbidities in diabetic patients.